The San Francisco Chronicle letter (part 3) reads as follows "Here is part of a cipher the other 2 parts of this cipher are being mailed to the editors of the Vallejo Times and SF Examiner. I want you to print this cipher on the front page of your paper. In this cipher is my idenity. If you do not print this cipher by the afternoon of Fry.1st of Aug 69, I will go on a kill ram-Page Fry. night. I will cruse around all weekend killing lone people in the night then move on to kill again, until I end up with a dozen people over the weekend." The final 18 characters of the San Francisco Chronicle code remain undeciphered. However, the clues to breaking the remaining portion of the cipher may reside within the letters themselves.
The 408 cipher message read "I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife. ebeorietemethhpiti." The unbroken characters are shown in red.
If the killer had already decided upon his pseudonym when he wrote the three July 31st 1969 letters, then his decision to begin all three letters with "This is the murderer" and "I am the killer" (twice) was deliberately engineered to withhold the pseudonym Zodiac from the letters. The reason being - it was concealed in the final 18 characters of the 408 cipher.
It could be argued, that if he was to reveal his identity or pseudonym in the 408 cipher, then logically he would sign off the cryptogram with it. This was also apparent in the 340 cipher, with the near-Zodiac tantalizingly placed on the final line.
If the Zodiac Killer had revealed his pseudonym straight away, then one of the letters would have opened with "This is the Zodiac" rather than "This is the murderer" (exactly like the August 4th 1969 letter). The other two letters would have opened with "I am the Zodiac Killer" rather than "I am the killer". But the murderer and author of the letters wanted to hide his pseudonym for now, and conceal it in the final 18 characters of the 408 cipher.
"I like killing people because it is so much fun it is more fun than killing wild game in the forrest because man is the most dangerous animal of all to kill something gives me the most thrilling experence it is even better than getting your rocks off with a girl the best part of it is that when I die I will be reborn in paradice and all the (people) I have killed will become my slaves. I will not give you my name because you will try to slow down or stop my collecting of slaves for my afterlife. I am the Zodiac Killer."
This is an attempt at reasoning a solution from within the letters themselves, and not a claim of a definitive solution
THE 18 UNSOLVED CHARACTERS [PT2]
THE 18 UNSOLVED CHARACTERS [PT3]